That's the version I am installing (see my post above where I say the install executable I am running). Ran that same executable from two different sources (one I personally downloaded, and one that somebody else had).

Not sure how this is happening, but we are trying to install from a version 5 install file onto a Windows 10 PC, and it is installing version 6. Of course when we try to put in the key for the version 5 it is telling us we need to upgrade (and pay for it of course).
Why would this be happening? Are we being forced to version 6? We are using this install file - pdfelement_setup_full1042 which we know to be version 5, but when you open the program, it is version 6 (see the attachment).